1. Field of the invention
The present invention is generally concerned with the display of information, in particular the display of prices or the like in retail stores, or stock data and the like, and it is more particularly concerned with a new system comprising a plurality of remote controlled display modules (also known as electronic labels) which can display variable data.
2. Description of the prior art
A number of systems of this type are known in the prior art.
In most known installations the electronic labels are connected to a central control computer via a bus type link typically comprising a power supply wire for the electronic circuitry of the labels and one or more wires for transmission of data between the computer and the labels.
Because of the presence of the cables, these systems are inconvenient to use, costly and unreliable. Also, they greatly complicate altering the layout of the store, as it is then necessary to modify the routing of the cables to adapt them to the new layout.
There is known from the patent FR-A-2 604 315 a two-way radio system linking a central unit and individual display modules in which the metal shelving for the products on sale is used to achieve electromagnetic coupling between a transmit antenna and the individual modules carried by said shelving.
A solution of this kind has a number of limitations, however. All shelving must be made from metals or alloys able to provide the coupling. The transmit antenna must be arranged so that sections of it extend along the upper surface of each shelving unit, which is inconvenient. Changing the layout of the store again implies total reconstruction of the antenna.
Finally, and most importantly, the display modules of this known system necessarily comprise two separate antennas for receiving a carrier and information proper, which increases their complexity and their cost.
The present invention is directed to alleviating these drawbacks of the prior art by proposing an installation which is economic, reliable and extremely flexible in relation to changing the layout of the retailing surfaces.